选择性激光熔化种植体对早期骨矿化沉积率的影响

目的：研究由选择性激光熔化（selective laser melting，SLM）技术制备的钛种植体的粗糙表面对种植体周围早期骨矿化沉积率的影响。方法：在两只成年雄性比格犬下颌骨愈合拔牙窝分别植入SLM种植体和大颗粒喷砂酸蚀（sandblasted, large grit, acid etched, SLA）种植体共16颗，分为埋入愈合和穿龈愈合即刻负重，在植入后2、4、8周分别注射3种四环素类荧光标记物，用以标记和观察新骨。植入12周时处死两只比格犬，制作硬组织切片共16张，经甲苯胺蓝染色后在光学显微镜和激光扫描共聚焦荧光显微镜下观察标本，对比各组种植体周围的新骨形成情况并计算平均骨矿化沉积率。结果：SLM种植体在植入术后12周与骨组织之间形成了良好的骨结合，新生骨在其粗糙表面爬行生长并渗透于孔隙之间，SLM种植体的平均骨矿化沉积率明显高于SLA种植体（P<0.01）。结论：SLM法制备的钛种植体可以促进种植体周围早期骨整合，提高早期骨矿化速率。

Influence of implants prepared by selective laser melting on early bone healing

Objective: To evaluate the influence of the rough surface of dental implants prepared by selective laser melting (SLM) on early bone healing around titanium implants. Methods: A total of sixteen titanium implants were involved in our research,of which eight implants were prepared by SLM (TIXOS (R) Cylindrical, Leader-Novaxa, Milan, Italy; 3. 3 mm × 10 mm, internal hex) and the other eight were sandblasted, large-grit and acid-etched (SLA) implants (IMPLUS (R) Cylindrical,Leader-Novaxa,Milan, Italy; 3. 3 mm x 10 mm, internal hex). All of the dental implants were inserted into the healed extraction sockets of the mandible of two adult male Beagle dogs. Half of the dental implants were designed to be healed beneath the mucosa and the other half were intended to be healed transgingivally and were immediately loaded by acrylic resin bridge restoration. Three types of tetracycline fluorescent labels, namely calcein blue, alizarin complexone and calcein, were administered into the veins of the Beagle dogs 2,4, and 8 weeks after implant placement respectively for fluorescent evaluation of newly formed bone peri-implant. Both Beagle dogs were euthanized 12 weeks after implant insertion and the mandible block specimens containing the titanium implants and surrounding bone and soft tissue of each dog were carefully sectioned and dissected. A total of 16 hard tissue slices were obtained and stained with toluidine blue for microscopic examination and histomorphometric measurements. Histological observation was made for each slice under light microscope and laser scanning confocal microscope (LSCM). Comparison on new bone formation around titanium implants of each group was made and mineral apposition rate (MAR) was calculated for each group. Results: Dental implants prepared by selective laser melting had achieved satisfying osseointegration to surrounding bone tissue after the healing period of 12 weeks. Newly formed bone tissue was observed creeping on the highly porous surface of the SLM implant and growing into the pores of surface structure. Higher MAR values were shown for SLM implants compared with SLA implants (P <0. 01 ). Conclusion: Dental implants prepared by selective laser melting could promote early bone healing and improve mineral apposition rate.